Speed &Amp; Fast Twitch Muscle Fibers

You Need More Than Aerobic Exercise

Every athlete at some point wishes to have more speed. Whether it be speed in terms of fast legs in a runner or fast arms in a boxer, it encompasses the same underlying principles. 

 To start off I’m going to retell how I discovered what was going on at the biological level with respect to speed. Around the time I started getting involved in sports in high school I suddenly became enthralled with this idea of being fast and strong. During my sophomore year I developed a great work ethic and began working out consistently and with a lot of effort. Despite the fact that I saw results I couldn’t help but notice that their were several people I knew who were lazy, barely ever worked out , ate terrible food and still managed to have ridiculous speed. It was at this moment I decided that their had to be something far greater at hand. While looking up if genetics could play a role in this I stumbled across Muscle Fibers.

 While reading up on this I discovered that their are basically 2 types of muscle fibers, Fast twitch and slow twitch. When we are born we are genetically coded for a predetermined amount of each. The average person usually has about half and half of each, but some people are genetically inclined to one or the other. This would account for some people just being naturally fast. Type 1, or slow twitch muscle fibers are very efficient at using oxygen which makes them ideal for muscle contractions over an extended period of time. Cross country or distance runners would ideally have more of these muscle fibers. Type 2, or fast twitch muscle fibers do the opposite. These use anaerobic energy, or function without oxygen so to speak. Fast twitch muscle fibers can be further broken down into 2a or 2b. 2a is just the intermediate of the two, sort of like a mix between the 2. And my favorite type 2b, is purely anaerobic and creates quick and powerful muscle contraction. These types of muscle fibers are more prominent amongst short sprinters e.g. Usain Bolt. 

 After figuring all this out I was happy to know that I could blame genetics for my speed or for other people being freakishly fast. After figuring this out what I needed to figure out was how best to train pre-existing fast twitch muscle fibers I already had and also whether or not it was possible to change ones muscle composition, for example going from half and half to maybe 60-65 % fast twitch. 

I believe the answer to that is yes. In some fairly recent studies done their has been evidence that type 1(slow twitch) and 2b(purely fast twitch) muscle fibers can indeed be altered with specific training routines. What many people really want to know is just how much these muscle fibers can actually transform, and to my knowledge I don’t believe anyone has figured this out yet. Personally I think it is somewhat limited, because at the end of the day your DNA is your DNA and it will always signal for the formation of the same proteins unless somehow manually manipulated.

That being said, what most (explosive)athletes usually want to do is trigger muscular growth in pre-existing fast twitch muscle fibers AND train the motor pathways, both of which go hand in hand. In order to develop your fast twitch muscle fibers the underlying principle is that you have to use them. So how do you use those fast anaerobic muscles?..with fast anaerobic exercises. For example using heavy weights with fast motion exercises is very effective in developing these 2b muscle fibers. The best exercises that I can think of right now would be a majority of the olympic lifts. Power cleans, Snatches, clean n jerks and so forth are all very explosive exercises which effectively activate fast twitch muscle fibers. Furthermore, these exercises are very effective in the sense that you use a lot of your body from your feet to legs to core and arm. A football player for example wants to reap the benefits of such an exercise because it helps them develop the strength needed to not only be explosive, but to be explosive from the ground up and carry that momentum forward. With respect to running the best way to stimulate these fast twitch muscle fibers tends to be with all out explosive sprints over a short distance. Such exercises could be practicing starts out of the blocks, 40 yard dashes and even all out sprint from 30-100 meters or so. The distance and exact routine would of course vary with your goals, but you get the idea.

Now what I believe, as well as many other professionals is that training the motor pathways is what really counts. Given whatever amount of fast twitch fibers you may have you need to be able to activate them at your own will for your best performance. When you decide to sprint you are essentially activating a neuron pathway from your brain to the fast twitch fibers in your legs and elsewhere. I like to think of this neuron pathway as a road. The more fast exercises you do the better paved your “road” is and the neuron message travels there much faster and smoother. This is the same underlying principle when people talk about muscle memory with other hands on activities. That being said I feel like to be fast or explosive you basically have to exercise in a similar manner. This isn’t to say that conditioning doesn’t have its place in a workout routine, but essentially you want to train how you want to perform.